The invention relates to an apparatus for successively making plastic bags.
There has been recently requested to successively make plastic bags each of which is completed with first and second gusset portions and a bottom gusset portion. The plastic bag includes two layers of panel portion superposed to define aligned top edges, first and second side edges and bottom edges. The first side gusset portion is disposed between the first side edges to extend therealong. The second side gusset portion is disposed between the second side edges to extend therealong. Each of the first and second side gusset portions is folded into halves along a center line extending longitudinally thereof, superposed into two layers and interposed between the layers of panel portion. The first side edges are connected with each other by the first side gusset portion, the second side edges being connected with each other by the second side gusset portion.
On the other hand, the bottom gusset portion is disposed between the bottom edges to extend therealong. The bottom gusset portion is also folded into halves along a center line extending longitudinally thereof, superposed into two layers and interposed between the layers of panel portion. The bottom edges are connected with each other by the bottom gusset portion. In addition, the bottom gusset portion has first and second ends at which first and second auxiliary gusset portions are formed. Each of the first and second auxiliary gusset portions is folded from the layers of bottom gusset portion along folded lines extending at an angle of about 45xc2x0 with respect to the center line of bottom gusset portion. The first auxiliary gusset portion is further folded into halves along a center line which is an extension of the center line of bottom gusset portion, to be superposed into two layers one of which is interposed along with one of the layers of bottom gusset portion between one of the layers of panel portion and one of the layers of first side gusset portion. The other layer of first auxiliary gusset portion is folded along with the other layer of bottom gusset portion between the other layer of panel portion and the other layer of first side gusset portion. The first side gusset portion is connected with the bottom gusset portion by the first auxiliary gusset portion. The second auxiliary gusset portion is further folded into halves along a center line which is an extension of the center line of bottom gusset portion, to be superposed into two layers one of which is interposed along with one of the layers of bottom gusset portion between one of the layers of panel portion and one of the layers of second side gusset portion. The other layer of second auxiliary gusset portion is folded along with the other layer of bottom gusset portion between the other layer of panel portion and the other layer of second side gusset portion. The second side gusset portion is connected with the bottom gusset portion by the second auxiliary gusset portion.
Accordingly, the plastic bag is advantageous in that the first and second side gusset portions can be unfolded between the first and second side edges respectively to obtain a large capacity. The bottom gusset portion and the first and second auxiliary gusset portions can also be unfolded between the bottom edges to constitute a rectangular bottom. The plastic bag can therefore stably stand on a table.
However, it has been heretofore difficult to successively the plastic bags.
It is therefore an object of the invention to provide a new and improved apparatus for successively making plastic bags each of which is completed with first and second side gusset portions and a bottom gusset portion.
According to the invention, an apparatus is arranged to successively make plastic bags each of which includes two layers of panel portion superposed to define aligned top edges, first and second side edges and bottom edges. The plastic bag further includes a first side gusset portion disposed between and extending along the first side edges, a second side gusset portion disposed between and extending along the second side edges, and a bottom gusset portion disposed between and extending along the bottom edges.
The apparatus comprises feeding means for feeding a main material intermittently for a length along a feeding path. The main material comprises the layers of panel portion and the first and second side gusset portions continuing longitudinally thereof respectively, the feeding means feeding the main material longitudinally of the layers of panel portion and the first and second side gusset portions. The apparatus further comprises cutting means disposed at a position predetermined along the feeding path for cutting one of the layers of panel portion as well as the first and second side gusset portions widthwise of the main material and leaving the other layer of panel portion continuing, to form an opening in the main material, whenever feeding the main material intermittently. The apparatus further comprises inserting means disposed downstream of the cutting means along the feeding path for inserting an additional material between the layers of panel portion through the opening, whenever feeding the main material intermittently. The additional material comprises the bottom gusset portion.
In a preferred embodiment, the cutting means comprises a Thomson blade extending widthwise of and opposed to one of the layers of panel portion. The cutting means further comprises drive means for moving the Thomson blade toward one of the layers of panel portion to cut one of the layers of panel portion as well as the first and second side gusset portions widthwise of the main material.
Each of the first and second side gusset portions is folded into halves along a center line extending longitudinally thereof, superposed into two layers and interposed between the layers of panel portion. The first side edges are connected with each other by the first side gusset portion, the second side edges being connected with each other by the second gusset portion. The bottom gusset portion is folded into halves along a center line extending longitudinally thereof, superposed into two layers and interposed between the layers of panel portion. The bottom edges are connected with each other by the bottom gusset portion. In addition, the bottom gusset portion has first and second ends at which first and second auxiliary gusset portions are formed. Each of the first and second auxiliary gusset portions is folded from the layers of bottom gusset portion along folded lines extending at an angle of about 45xc2x0 with respect to the center line of bottom gusset portion. The first auxiliary gusset portion is further folded into halves along a center line which is an extension of the center line of bottom gusset portion, to be superposed into two layers one of which is interposed along with one of the layers of bottom gusset portion between one of the layers of panel portion and one of the layers of first side gusset portion. The other layer of first auxiliary gusset portion is interposed along with the other layer of bottom gusset portion between the other layer of panel portion and the other layer of first side gusset portion. The first side gusset portion is connected with the bottom gusset portion by the first auxiliary gusset portion. The second auxiliary gusset portion is further folded into halves along a center line which is an extension of the center line of bottom gusset portion, to be superposed into two layers one of which is interposed along with one of the layers of bottom gusset portion between one of the layers of panel portion and one of the layers of second side gusset portion. The other layer of second auxiliary gusset portion is interposed along with the other layer of bottom gusset portion between the other layer of panel portion and the other layer of second side gusset portion. The second side gusset portion is connected with the bottom gusset portion by the second auxiliary gusset portion.
The inserting means comprises a spatula adapted to be pressed against the center line of bottom gusset portion to insert the additional material between the layers of panel portion through the opening.
The apparatus further comprises guide means through which the additional material passes to be folded along the center line of bottom gusset portion and the folded lines of first and second auxiliary gusset portions, when inserting the additional material by the spatula.
The apparatus further comprises folded tendency making means for making the additional material having a tendency to be folded along the center line of bottom gusset portion and the folded lines of first and second auxiliary gusset portions, the spatula being pressed against the center line of bottom gusset portion to insert the additional material, after making the additional material having a tendency to be folded.
In other embodiment, the inserting means comprises an autohand arranged to clamp or suctionally attract the additional material which has been previously folded along the center line of bottom gusset portion, the folded lines of first and second auxiliary gusset portions and the center lines of first and second auxiliary gusset portions, the auto hand inserting the additional material between the layers of panel portion through the opening.
The apparatus further comprises bottom gusset sealing means disposed downstream of the inserting means along the feeding path for heat sealing the layers of panel portion with the layers of bottom gusset portion and heat sealing the layers of first and second auxiliary gusset portions with the layers of first and second side gusset portions along the opening respectively, whenever feeding the main material intermittently.
A cutter is disposed downstream of the bottom gusset sealing means along the feeding path for cutting the other layer of panel portion along the opening to form the bottom edges of plastic bag, whenever feeding the main material intermittently.
The cutter may be arranged to cut the other layer of panel portion as well as one of the layers of panel portion, the layers of bottom gusset portion, the layers of first and second auxiliary gusset portions and the layers of first and second side gusset portions along the opening to form the bottom edges of plastic bag.
The cutter may be further arranged to cut the other layer of panel portion as well as one of the layers of panel portion, the layers of bottom gusset portion, the layers of first and second auxiliary gusset portion and the layers of first and second side gusset portions at two positions predetermined downstream and upstream of the opening.
The apparatus may further comprises side gusset sealing means disposed upstream of the inserting means along the feeding path for heat sealing the layers of panel portion with the layers of first and second side gusset portions along the first and second side edges respectively so as to form non-sealing portions within the range of seal width, whenever feeding the main material intermittently. The non-sealing portions are spaced from each other along the first and second side edges. The inserting means then inserts the additional material between the layers of panel portion to make the bottom gusset portion and the first and second auxiliary gusset portions invading the non-sealing portions. The bottom sealing means then heat seals the layers of panel portion with the layers of bottom gusset portion and heat seals the layers of first and second auxiliary gusset portion with the layers of first and second side gusset portion along the opening respectively.
The bottom gusset sealing means may be arranged to further heat seal the layers of panel portion with the layers of bottom gusset portion and the layers of first and second side gusset portions and heat seal the layers of first and second auxiliary gusset portions with the layers of first and second side gusset portions at corners between the bottom edges and the first and second side edges respectively, to form joining lines extending to traverse obliquely the bottom edges and the first and second side edges.
The joining lines may comprise straight or curved lines.
The cutter may be arranged to cut the layers of panel portion, the layers of bottom gusset portion, the layers of first and second auxiliary gusset portions and the layers of first and second side gusset portions along the joining lines.
According to the invention, there is also provided a plastic bag in which the layers of panel portion are heat sealed with the layers of bottom gusset portion along the bottom edges respectively so that the bottom edges are connected with each other by the bottom gusset portion. The layers of first and second auxiliary gusset portions are heat sealed with the layers of first and second side gusset portions along the bottom edges respectively so that the first and second side gusset portions are connected with the bottom gusset portion by the first and second auxiliary gusset portions. In addition, the layers of panel portion are heat sealed with the layers of first and second side gusset portions along the first and second side edges respectively so that the first side edges are connected with each other by the first side gusset portion, the second side edges being connected with each other by the second side gusset portion. The bottom gusset portion and the first and second auxiliary gusset portions invade the ranges of seal width of the layers of panel portion with the layers of first and second side gusset portions.
There is also provided a plastic bag in which the first side edges are connected with each other by the first side gusset portion, the second side edges being connected with each other by the second side gusset portion, the bottom edges being connected with each other by the bottom gusset portion. The plastic bag includes joining lines formed at corners between the bottom edges and the first and second side edges and extending to traverse obliquely the bottom edges and the first and second side edges. The layers of panel portion are joined with the layers of bottom gusset portion and the layers of first and second side gusset portions along the joining lines. The layers of first and second auxiliary gusset portions are joined with the layers of first and second side gusset portions along the joining lines so that the first and second side gusset portions are connected with the bottom gusset portion by the first and second auxiliary gusset portions.
In the plastic bag, the joining lines may comprise heat seal lines, the layers of panel portion being heat sealed and joined with the layers of bottom gusset portion and the layers of first and second side gusset portions along the heat seal lines, the layers of first and second auxiliary gusset portions being heat sealed and joined with the layers of first and second side gusset portions along the heat seal lines.
The joining lines may comprise straight or curves lines.
It is preferable that the layers of panel portion, the layers of bottom gusset portion, the layers of first and second auxiliary gusset portions and the layers of first and second side gusset portions are corner cut along the joining lines.
It is also preferable that the layers of panel portion are spot joined with the layers of bottom gusset portion, the layers of first and second auxiliary gusset portions and the layers of first and second side gusset portions respectively at positions adjacent the bottom edges and between the center lines of the first and second side gusset portions and the joining lines.